Environment conservation and energy saving are matters of increasing concern to the public, wherein the reduction of electric lighting energy is particularly of economical value and practical to implement. To this end, various energy saving light control lamps or switches have been developed, for example, CN 2181159 disclosed an energy saving lamp wherein the onoff of the lamp is controlled with a photoresistor and a thyristor, but which is basically adapted for use in low power illumination. CN 2468257 disclosed a light control lamp having a light control switch, wherein the photosensitivity and onoff of the lamp are controlled with a photoresistor, a potentiometer, an integrated triggering block and a relay. While it employs elements having relatively large sizes, e.g. transformer, potentiometer and relay, the ohmic dissipation thereof is relatively high and a relatively large space is also required for proper installation.
Further, a lamp bulb or a lamp tube is more and more commonly replaced in various places with a compact type fluorescent lamp. While there is a very limited space for installation of the compact type fluorescent lamp, such light control lamps cannot be adapted for use therewith in view of their dimension and other factors, such as the parts being employed therein or the like. To this end, CN patent application number 200610009296.9 submitted by the same applicant of the present patent application disclosed a light control fluorescent lamp, and more particularly a compact type light control fluorescent lamp and its light control circuit, wherein two programmable integrated circuits IC1, IC2 are employed to control or adjust the photosensitivity and onoff thereof in a relatively accurate manner such that the lamp is not susceptible to a sudden change of the ambient brightness. The cost of such compact type light control fluorescent lamp is relatively high as it employs two integrated circuits. Whereas the body of the compact type light control fluorescent lamp is generally of spherical or round shape, the coverage of the single photoresistor might probably be restricted such that under certain circumstances it will operate improperly. For example, it will erroneously turn off while it was irradiated at a direction for a relatively long duration by a head light of a vehicle amid traffic congestion, and besides, it will erroneously turn on while the photoresistor thereof being obstructed by chance.